Control moment gyroscope arrays, reaction wheel arrays, and other such devices deployed onboard spacecraft for attitude adjustment purposes generate vibratory forces during operation. Vibration isolation systems are commonly employed to minimize the transmission of vibratory forces emitted from such attitude adjustment devices, through the spacecraft body, to any vibration-sensitive components (e.g., optical payloads) carried by the spacecraft. Vibration isolation systems commonly include a number of individual vibration isolators (typically three to eight isolators), which are positioned between the spacecraft payload and the spacecraft body in a multi-point mounting arrangement. The performance of a vibration isolation systems is largely determined by the number of isolators included within the system, the manner in which the isolators are arranged, and the vibration attenuation characteristics of each individual isolator. Vibration isolation system employing three parameter isolators, which behave mechanically as a primary spring in parallel with a series-coupled secondary spring and damper, provide superior attenuation of high frequency vibratory forces (commonly referred to as “jitter”) as compared to vibration isolation systems employing other types of passive isolators, such as viscoelastic isolators. The three parameter isolators are advantageously implemented as single degree of freedom (“DOF”) devices, which provide damping along a single longitudinal axis. An example of a single DOF, three parameter isolator is the D-STRUT® isolator developed and commercially marketed by Honeywell, Inc., currently headquartered in Morristown, N.J.
Three parameter isolators are often equipped with a thermal compensation device, which regulates the pressure of the damping fluid within the damper assembly as damping fluid volume fluctuates due to changes in temperature. By common design, the thermal compensator is nested within the damper assembly housing. As the result of such a nested design, the dimensions and the operational capabilities of the thermal compensator are inherently limited by the size of the damper assembly. In instances wherein the three parameter isolator need only operate in low impact, short stroke range environments of the type encountered on-orbit, such design constraints may be acceptable as the operative temperature range and variations in damping fluid volume also tend to be relatively limited. However, in instances wherein the three parameter isolator need also operate under high impact, long stroke range conditions, it may be desirable for the thermal compensator to regulate fluid pressure within the damper assembly at relatively high operating temperatures. While certain dimensions (e.g., the outer diameter) of the damper assembly can be increased to allow a corresponding increase in the size of the thermal compensator components, this results in significant penalties in the overall size and weight of the three parameter isolator. Such an increase in thermal compensator size also results in undesirable increase in the overall size of the thermal compensator chamber and, therefore, an increase in the overall volume and weight of the damping fluid.
It is thus desirable to provide embodiments of an isolator, such as a three parameter isolator, having a thermal compensator suitable for regulating damping fluid pressure within a damper assembly under long stroke/high impact load operating conditions. Ideally, embodiments of such an isolator would allow the overall size and weight of the damper assembly to be minimized, while also allowing greater freedom in selection the thermal compensator components to, for example, enable the thermal compensator to be imparted with relatively high starting pressure and/or to allow a reduction in the overall volume and weight of the damping fluid. More generally, it would be desirable to provide embodiments of spacecraft isolation systems employing a number of such isolators. Other desirable features and characteristics of embodiments of the present invention will become apparent from the subsequent Detailed Description and the appended Claims, taken in conjunction with the accompanying drawings and the foregoing Background.